Gas turbines used in the electrical power generation industry include combustors which burn an air-fuel mixture. The expanding gases are then routed into the turbine section to generative motive force. The combustors typically include a cylindrical combustion liner 100, as shown in FIG. 1. The combustion of the air-fuel mixture occurs inside the cylindrical combustion liner.
After a combustion liner 100 has been used in a gas turbine for an extended period of time, it is necessary to repair and recondition the combustion liner 100. Part of the repair and reconditioning process involves sandblasting the interior cylindrical surface of the combustion liner to remove any buildup of combustion byproducts.
One way to accomplish sandblasting of the interior cylindrical surface is to place the combustion liner in a blast room, and then manually direct a flow of grit along the interior cylindrical surface of the combustion liner to remove contaminants. An operator typically holds a hose that supplies a flow of grit delivered under pressure, and the operator directs the flow of grit onto the interior cylindrical surface of the combustion liner 100. Unfortunately, it is very difficult for an operator to evenly or uniformly sandblast the entire interior cylindrical surface.
Another option is to purchase a self-contained sandblasting unit which is designed to automatically sandblast such objects. A self-contained sandblasting unit typically includes an enclosure, a mounting system for mounting a cylindrical object inside the enclosure, a grit supply and recovery system, and a movable blast head which can be programmed to move in an automated fashion. The blast head moves automatically under the direction of a processor to direct a flow of grit along the interior cylindrical surface of a combustion liner to remove any contaminants.
Although a self-contained sandblasting unit can conduct a more uniform sandblasting operation on the interior of a cylindrical combustion liner than a manual sandblasting operation, these self-contained sandblasting units are relatively expensive. For this reason, many in the industry prefer to manually sandblast combustion liners, even though it will result in less uniform results.